Gas Burner

ABSTRACT

A gas burner comprising a burner pot ( 2 ) supporting a burner body ( 6 ) comprising a series of peripherally distributed flame orifices ( 8 ), a gas injector ( 13 ) and a gas supply tube ( 11 ) provided with a collar ( 12 ), which are joined to the burner pot; the burner pot is provided with a bottom ( 9 ) which has a smooth walled central orifice ( 10 ); the extremity ( 17 ) of the supply tube is fitted, without any significant amount of clearance via the underneath part of the bottom ( 9 ) of the burner pot, inside the orifice ( 10 ) with the collar ( 12 ), resting against the lower surface of the bottom ( 9 ); the injector ( 13 ) is screwed, from above the bottom ( 9 ), into the extremity of the supply tube ( 11 ); and the injector ( 13 ) is configured in such a way as to push back the wall of the extremity of the supply tube ( 11 ) into a tight resting position against the wall of the orifice ( 10 ).

The present invention generally relates to the field of gas burners for a domestic cooking device, and it relates more specifically to improvments made to gas burners comprising a burner pot supporting a burner body having at least one set of peripherally distributed flame orifices, a gas injector and a gas supply tube, furnished with a collar, being connected to said burner pot.

The gas burners of the related type are routinely fitted to domestic cooking devices (stoves, hotplates). However, the burners currently manufactured have various drawbacks or disadvantages that are both structural and cost-related.

Normally, the injector and the supply tube are each fixedly attached to the burner pot by screwing.

Accordingly, the bottom of the pot is provided with a tapped central orifice capable of receiving the gas injector which, itself, is threaded externally at least over a portion of its height. However, the machining of a tapped orifice in the material forming the burner pot, usually cast aluminum, causes a removal of the superficial annealing at least in certain locations (slivers) on the edge of the orifice, these slivers revealing the underlying porous material. The result of this is a considerable proportion (20 to 30%) of burner pots that have to be scrapped.

For the attachment of the supply tube, a similar difficulty may arise if the burner pot is provided with another orifice suitable for receiving a connection end-piece mounted by screwing.

In addition, irrespective of how the end of the tube is mounted on the burner pot, the latter must be equipped appropriately. In particular, in the case of burners under which the available height in the cooking device is very slight, it is known practice to design the burner pot with an integral end-piece, incorporating the connection orifice, which extends substantially perpendicular to the axis of the burner. However, such an integral end-piece represents a substantial protrusion and requires material which increases the manufacturing cost of the burner pot. In addition, the presence of this end-piece complicates the production of the burner pot manufacturing mold and increases the cost of manufacturing this mold.

As for what is now the assembly of the various component parts of the burner, these assemblies carried out by screwing demand time and personnel and finally are costly.

The manufacturers of cooking devices are constantly and urgently seeking ever lower production costs, which results in the component elements, and particularly the burners, being, for their part, manufactured in the most economical conditions possible.

The main object of the invention is to satisfy, at least in part, the requirements of the art and to propose an enhanced structure of a gas burner of the aforementioned type that leads to simplified manufacture and easy assemblies, and that consequently provides significant cost savings with respect to the manufacture and installation of these burners.

To these ends, the invention proposes a gas burner as mentioned in the preamble that is characterized, being arranged according to the invention, by the combination of the following features:

-   -   the burner pot has a bottom furnished with a smooth-walled         central orifice,     -   the end of the supply tube is sleeve-fitted with no notable         clearance, from underneath the bottom of the burner pot, into         the orifice with the collar pressing against the bottom face of         the bottom of the burner pot,     -   the injector is screwed, from the top of the bottom of the         burner pot, into the end of the supply tube, and     -   the injector is arranged to push away the end wall of the supply         tube pressing in a sealed manner against the wall of the         orifice.

A gas burner arranged according to the dispositions of the invention joins many advantages.

The fact that the orifice provided in the bottom of the burner pot is provided with a smooth-faced wall considerably simplifies manufacture. Specifically, the orifice may be obtained by a simple stamping of the burner pot bottom, by applying a known technique that is effective with the material forming the burner pot. It is therefore possible to form an orifice with a clean wall and an undamaged edge, without slivers, and having the required diameter with sufficient precision.

In addition, because of the quality obtained during the formation of the single orifice, there are virtually no defective parts: the rate of production of correct parts is considerably increased and the economic gain is very great.

The mounting of the injector in the end of the supply tube means that these two components are simultaneously fixedly attached to the burner pot through the same orifice. It is therefor appropriate to provide only one orifice, which dispenses with the operation for forming the second orifice required in the conventional structure of the burner.

What is more, the assembly process is remarkably simplified: sleeve-fitting the end of the supply tube into the orifice, followed by screwing the injector into the end of said tube is sufficient not only to attach these two components to the burner pot, but also to seal this assembly automatically during screwing. These two operations of sleeve-fitting and screwing require no particular technical skill and may be carried out by personnel of low qualification.

In a preferred embodiment, the collar is integral with the supply tube and formed by a folding of the wall of said tube. The manufacture of a tube having an end thus formed is more economical than the conventionally adopted solutions, with provision and fixed attachment of an external collar. In addition, to form a burner of low height, use is made of a supply tube that is bent, particularly substantially at 90°, and the supply tube bending operation may be carried out jointly with the operation to form the collar.

Still in the context of a preferred embodiment, provision can be made for the injector to be externally frustoconical at least in part. Advantageously then, it is the portion of the injector that is situated above its threaded portion, between the latter and the head of the injector, that is frustoconical.

In practice, it is possible to arrange matters so that the terminal portion of the end of the supply tube that extends beyond the collar has a length substantially equal to the thickness of the bottom of the burner pot.

Finally, with regard to the end of the supply tube, it may be tapped internally while the injector is furnished with a standard thread, or else, more economically and therefore preferred, the inner face of the wall of the end of the tube remains smooth while the injector is furnished with a self tapping thread.

The invention will be better understood on reading the following detailed description of a preferred embodiment given only as a purely illustrative example. In this description, reference is made to the appended drawing in which the single figure is a side view in diametric section of a gas burner arranged according to the invention.

The gas burner illustrated in the figure, indicated in its entirety by reference number 1, conventionally comprises a burner pot 2 arranged to be attached to a support belonging to a cooking device, usually a top plate of this device (in the example illustrated, the burner pot 2 is attached to a plate-shaped portion 3 of said top plate 4, overhanging the rest of the plate). On this burner pot there rests, by feet 5 (only one foot is visible in the figure), a burner body 6 furnished, on its top edge, with peripherally distributed notches. On the burner body there rests a cap 7 that closes off the aforementioned notches from the top to form flame orifices 8.

In the example illustrated, the burner pot 2 is arranged with a bottom 9 of substantially generally flat shape, but this configuration is not linked to the dispositions characteristic of the invention that will be explained hereinafter.

The bottom 9 of the burner pot 2 is furnished with a smooth-walled central hole or orifice 10 that may be formed by stamping of the bottom.

A gas supply tube 11 has its end sleeve-fitted without notable clearance, that is to say with a clearance that is strictly necessary for the insertion, from underneath the bottom 9 of the burner pot 2, into the orifice 10. The tube 11 is furnished with a collar 12 that limits the insertion of the end of the supply tube 11 into the orifice 10, said collar 12 pressing against the bottom face of the bottom 9.

An injector 13, partly threaded externally at 15, is screwed, from the top of the bottom 9 of the burner pot 2, into the end of the supply tube 11.

There are many ways of fitting the end of the supply tube 11 with a collar. However, the simplest and most economical solution in practice consists in the collar 12 being produced integrally with the supply tube 11 and formed of a folding of the wall of said tube 11 according to a known technique.

The injector 13, for its part, is arranged to push away the wall of the end of the supply tube 11 against the smooth wall of the orifice 10 in order to establish with the latter a gas-tight contact. For this purpose, various dispositions known to those skilled in the art can be applied. Preferably however, a simple technical solution consists in the injector being externally frustoconical at least in part; particularly, as illustrated in the figure, the frustoconical portion 14 of the injector 13 is situated above its threaded portion 15, between the latter and the head 16 of the injector. When the injector is screwed into the end of the supply tube 11, the frustoconical portion 14 comes into contact with the edge of the tube 11 and spreads the latter radially while forcing it against the smooth wall of the orifice 10 of the bottom 9 of the burner pot. In this way a sealed mounting is achieved without additional parts and with no other manipulation than the screwing of the injector.

It must be emphasized that the end of the supply tube 11 may be threaded internally to receive the injector, or else preferably, because of the simplicity and of the minimal cost of this technical solution, the injector may be furnished with a self-tapping thread capable of being screwed into the end of the internally smooth supply tube.

This disposition of the invention will be easier to apply if, as illustrated in the figure, the terminal portion 17 of the end of the supply tube that extends beyond the collar 12 has a length substantially equal to the thickness of the central portion of the bottom 9 of the burner pot. It will be noted that this central portion of the bottom 9 of the burner pot may be made thicker than the rest of the bottom, for example by providing an extra thickness in the form of a plate 18 as shown in the figure, in order to reinforce the bottom 9 and/or to procure a bearing height of the tube on the wall of the orifice 10 that is sufficient to achieve the necessary seal in a secure manner and/or to wedge the injector in a correct vertical position relative to the burner body 6.

To form a low height burner as may be required for certain cooking device such as hotplates, the tube 11 may be bent, particularly substantially by 90°, under the collar. In an economic manner, the formation of the integral collar 12 and the bending of the tube may be carried out during a single operation.

Thanks to the dispositions according to the invention, a gas burner of the usual type is made with a minimum number of components (only three components for the bottom portion of the burner) and these components are assembled with fewer, simple manipulations. Such a gas burner is therefore able to be manufactured in particularly favorable economic conditions. 

1. A gas burner comprising a burner pot supporting a burner body having at least one set of peripherally distributed flame orifices, a gas injector and a gas supply tube, furnished with a collar, being connected to said burner pot, wherein the following features are combined: the burner pot has a bottom furnished with a smooth-walled central orifice, the end of the supply tube is sleeve-fitted with no notable clearance, from underneath the bottom of the burner pot, into the orifice with the collar pressing against the bottom face of the bottom of the burner pot, the injector is screwed, from the top of the bottom of the burner pot, into the end of the supply tube, and the injector is arranged to push away the end wall of the supply tube pressing in a sealed manner against the wall of the orifice.
 2. The gas burner as claimed in claim 1, wherein said collar is integral with the supply tube and formed by a folding of the wall of said tube.
 3. The gas burner as claimed in claim 1, wherein said injector is externally frustoconical at least in part.
 4. The gas burner as claimed in claim 3, wherein the frustoconical portion of the injector is situated above its threaded portion.
 5. The gas burner as claimed in claim 1, wherein a terminal portion of the end of the supply tube that extends beyond the collar has a length substantially equal to the thickness of the bottom of the burner pot.
 6. The gas burner as claimed in claim 1, wherein said supply tube is bent beneath the collar.
 7. The gas burner as claimed in claim 6, wherein said supply tube is bent substantially at 90°.
 8. The gas burner as claimed in claim 1, wherein the end of the supply tube is tapped internally while the injector is furnished with a standard thread.
 9. The gas burner as claimed in claim 1, wherein the inner face of the wall of the end of the supply tube is smooth while the injector is furnished with a self-tapping thread. 